# coding=utf-8
from xml import etree

import re
import random
import bbcode

from urllib.parse import unquote

from django.core.exceptions import ObjectDoesNotExist
from django.urls import reverse
from django.utils.translation import ugettext_lazy as _

import boards
from boards import settings
from swineboard.settings import ALLOWED_HOSTS


__author__ = 'neko259'


REFLINK_PATTERN = re.compile(r'^\d+$')
GLOBAL_REFLINK_PATTERN = re.compile(r'(\w+)::([^:]+)::(\d+)')
MULTI_NEWLINES_PATTERN = re.compile(r'(\r?\n){2,}')
ONE_NEWLINE = '\n'
REGEX_URL = re.compile(r'https?\://[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,3}(/\S*)?')
LINE_BREAK_HTML = '<div class="br"></div>'
SPOILER_SPACE = '&nbsp;'
REGEX_ANY_LINE_BREAK = re.compile(r'(' + LINE_BREAK_HTML + '|\r|\n)')
QUOTE_REPLACEMENT = '\g<1>&gt;'

MAX_SPOILER_MULTIPLIER = 2
MAX_SPOILER_SPACE_COUNT = 20


class TextFormatter:
    """
    An interface for formatter that can be used in the text format panel
    """

    def __init__(self):
        pass

    name = ''

    # Left and right tags for the button preview
    preview_left = ''
    preview_right = ''

    # Tag name to enclose the text in the form
    tag_name = ''

    has_input = 'false'
    input_prompt = ''


class AutolinkPattern:
    def handleMatch(self, m):
        link_element = etree.Element('a')
        href = m.group(2)
        link_element.set('href', href)
        link_element.text = href

        return link_element


class QuotePattern(TextFormatter):
    name = '>q'
    preview_left = '<span class="quote">'
    preview_right = '</span>'

    tag_name = 'quote'


class SpoilerPattern(TextFormatter):
    name = 'spoiler'
    preview_left = '<span class="spoiler">'
    preview_right = '</span>'

    tag_name = 'spoiler'


class CommentPattern(TextFormatter):
    name = ''
    preview_left = '<span class="comment">// '
    preview_right = '</span>'

    tag_name = 'comment'


# TODO Use <s> tag here
class StrikeThroughPattern(TextFormatter):
    name = 's'
    preview_left = '<span class="strikethrough">'
    preview_right = '</span>'

    tag_name = 's'


class ItalicPattern(TextFormatter):
    name = 'i'
    preview_left = '<i>'
    preview_right = '</i>'

    tag_name = 'i'


class BoldPattern(TextFormatter):
    name = 'b'
    preview_left = '<b>'
    preview_right = '</b>'

    tag_name = 'b'


class CodePattern(TextFormatter):
    name = 'code'
    preview_left = '<code>'
    preview_right = '</code>'

    tag_name = 'code'


class HintPattern(TextFormatter):
    name = 'hint'
    preview_left = '<span class="hint">'
    preview_right = '</span>'

    tag_name = 'hint'


class ColorPattern(TextFormatter):
    name = 'color'
    preview_left = '<span style="color:yellow;">'
    preview_right = '</span>'

    tag_name = 'color'

    has_input = 'true'
    input_prompt = _('Enter color (name or #ccc code)')


def render_reflink(tag_name, value, options, parent, context):
    result = '>>%s' % value

    post = None
    if REFLINK_PATTERN.match(value):
        post_id = int(value)

        try:
            post = boards.models.Post.objects.get(id=post_id)

        except ObjectDoesNotExist:
            pass
    elif GLOBAL_REFLINK_PATTERN.match(value):
        match = GLOBAL_REFLINK_PATTERN.search(value)
        try:
            global_id = boards.models.GlobalId.objects.get(
                key_type=match.group(1), key=match.group(2),
                local_id=match.group(3))
            post = global_id.post
        except ObjectDoesNotExist:
            pass

    if post is not None:
        result = post.get_link_view()

    return result


def render_quote(tag_name, value, options, parent, context):
    source = options.get('quote') or options.get('source')

    if source:
        result = '<div class="multiquote"><div class="quote-header">%s</div><div class="quote-text">%s</div></div>' % (source, value)
    else:
        # Insert a ">" at the start of every line
        result = '<span class="quote">&gt;{}</span>'.format(
            REGEX_ANY_LINE_BREAK.sub(QUOTE_REPLACEMENT, value))

    return result


def render_hint(tag_name, value, options, parent, context):
    if 'hint' in options:
        hint = options['hint']
        result = '<span class="hint" title="{}">{}</span>'.format(hint, value)
    else:
        result = value
    return result


def render_notification(tag_name, value, options, parent, content):
    username = value.lower()

    return '<a href="{}" class="user-cast">@{}</a>'.format(
        reverse('notifications', kwargs={'username': username}), username)


def render_tag(tag_name, value, options, parent, context):
    tag_name = value.lower()

    tag = boards.models.Tag.objects.get_by_alias(tag_name)
    if tag:
        url = tag.get_view()
    else:
        url = tag_name

    return url


def render_spoiler(tag_name, value, options, parent, context):
    if settings.get_bool('Forms', 'AdditionalSpoilerSpaces'):
        text_len = len(value)
        space_count = min(random.randint(0, text_len * MAX_SPOILER_MULTIPLIER),
                MAX_SPOILER_SPACE_COUNT)
        side_spaces = SPOILER_SPACE * (space_count // 2)
    else:
        side_spaces = ''
    return '<span class="spoiler">{}{}{}</span>'.format(side_spaces,
            value, side_spaces)


formatters = [
    QuotePattern,
    SpoilerPattern,
    ItalicPattern,
    BoldPattern,
    CommentPattern,
    StrikeThroughPattern,
    CodePattern,
    HintPattern,
    ColorPattern,
]


PREPARSE_PATTERNS = {
    r'(?<!>)>>(\d+)': r'[post]\1[/post]',  # Reflink ">>123"
    r'^>([^>].+)': r'[quote]\1[/quote]',  # Quote ">text"
    r'^//\s?(.+)': r'[comment]\1[/comment]',  # Comment "//text"
    r'\B@(\w+)': r'[user]\1[/user]',  # User notification "@user"
}

for hostname in ALLOWED_HOSTS:
    if hostname != '*':
        PREPARSE_PATTERNS[r'https?://{}/thread/\d+/#(\d+)/?'.format(hostname)] = r'[post]\1[/post]'
        PREPARSE_PATTERNS[r'https?://{}/thread/(\d+)/?'.format(hostname)] = r'[post]\1[/post]'


class Parser:
    def __init__(self):
        # The newline hack is added because br's margin does not work in all
        # browsers except firefox, when the div's does.
        self.parser = bbcode.Parser(newline=LINE_BREAK_HTML)

        self.parser.add_formatter('post', render_reflink, strip=True)
        self.parser.add_formatter('quote', render_quote, strip=True)
        self.parser.add_formatter('hint', render_hint, strip=True)
        self.parser.add_formatter('user', render_notification, strip=True)
        self.parser.add_formatter('tag', render_tag, strip=True)
        self.parser.add_formatter('spoiler', render_spoiler, strip=True)
        self.parser.add_simple_formatter(
            'comment', '<span class="comment">// %(value)s</span>', strip=True)
        self.parser.add_simple_formatter(
            's', '<span class="strikethrough">%(value)s</span>')
        self.parser.add_simple_formatter('code',
                                         '<pre><code>%(value)s</pre></code>',
                                         render_embedded=False,
                                         escape_html=True,
                                         replace_links=False,
                                         replace_cosmetic=False)

    def preparse(self, text):
        """
        Performs manual parsing before the bbcode parser is used.
        Preparsed text is saved as raw and the text before preparsing is lost.
        """
        new_text = MULTI_NEWLINES_PATTERN.sub(ONE_NEWLINE, text)

        for key, value in PREPARSE_PATTERNS.items():
            new_text = re.sub(key, value, new_text, flags=re.MULTILINE)

        for link in REGEX_URL.findall(text):
            new_text = new_text.replace(link, unquote(link))

        return new_text

    def parse(self, text):
        return self.parser.format(text)


parser = Parser()


def get_parser():
    return parser